The capacity to fold and assemble nascent unfolded proteins and to degrade unassembled and misfolded proteins is important to organelle homeostasis and is regulated by unfolded protein responses activated by specific stress signals. Defects in mitochondrial protein folding play a role in important neurological diseases such as spastic paraplegia and Parkinson's disease. My goal is to understand how mitochondria regulate their ability to fold and process proteins in response to variations in unfolded protein load. I will identify genes required for signaling the mitochondrial unfolded protein response by a systematic, sequential, genome-wide survey for C. elegans genes whose inactivation by RNAi impairs the mitochondrial unfolded protein response. I will prioritize and validate the genes identified in this survey based on biochemical assays that measure mitochondrial protein folding capacity, degradation capacity and import capacity in living C. elegans. Finally I will seek to identify the mode of action of genes that signal the mitochondrial unfolded protein response. By understanding the basic principles of signaling from the mitochondria to the nucleus I expect to provide insight into pathophysiological processes involved in neurodegeneration.